Pinocchio: The Series
Anime television series Pinocchio: The Series (Kashi no ki Mokku) is a longform adaptation of Pinocchio, in which the young puppet boy makes mistakes and learns hard lessons on his journey to becoming a real boy. In this series of 52 episodes, Pinocchio meets many varied characters, and there's a two-episode arc where he encounters mermaids. Well, Pinocchio at first encounters one mermaid, who's been captured and is displayed in a carnival tank.
Pinocchio helps the mermaid escape and, believing that she can help turn him into a human boy, helps her return home. Unfortunately most of the other mermaids have been captured by pirates, save for the mermaid's elderly grandmother. She, however confirms to Pinocchio that she cannot make him a real boy, and so he turns on them by teaming up with the pirates in order to get the mermaids to reveal their treasure. But Pinocchio learns a lesson and makes the right choice in the end, and helps free the mermaids before returning home.
